What is TSC?

Tuberous sclerosis complex (TSC) is a genetic disorder that causes non-malignant tumors to form in many different organs, primarily in the brain, eyes, heart, kidney, skin and lungs.

The aspects of TSC that most strongly impact quality of life are generally associated with the brain: seizures, developmental delay, intellectual disability and autism. However, many people with TSC are living independent, healthy lives and enjoying challenging professions such as doctors, lawyers, educators and researchers.  The incidence and severity of the various aspects of TSC vary widely between individuals—even between identical twins. Seizures remain one of the most common neurological features of TSC, occurring in 85% of individuals with TSC; therefore, the early diagnosis and treatment of these seizures are critically important.

How Many People Have TSC?

At least two children born each day will have tuberous sclerosis complex. Current estimates place tuberous sclerosis complex-affected births at one in 6,000. Nearly 1 million people worldwide are estimated to have TSC. Many cases may remain undiagnosed for years or decades due to the relative obscurity of the disease and the mild form symptoms may take in some people.

How Does a Person Develop TSC?


How is TSC Diagnosed?

Because TSC can manifest in so many different ways, diagnosis is generally made when physicians identify any two major features of TSC in one individual.  One major feature is cardiac rhabdomyoma, an abnormal growth in the heart muscle generally found in young children and sometimes found by ultrasound examination during pregnancy.  Other major features include specific abnormal skin growths or skin pigmentation, specific non-malignant tumors or growths such as subependymal nodules or subependymal giant cell astrocytomas (SEGAs) in the brain, lymphangioleiomyomatosis (LAM) in the lungs, angiomyolipomas in the kidney(s), and tubers in the brain or hamartomas in the eye.  Also, there are other minor features of TSC that might be diagnostic if found with a major feature in the same person.  TSC can also be diagnosed by genetic testing described below.

What Genes are Responsible for TSC?


How Can So Many Different Organs Be Affected by TSC?

Both the TSC1 and TSC2 genes suppress tumor growth in the body by carefully regulating cell growth through inhibition of a protein called mammalian target of rapamycin, or mTOR for short. When either the TSC1 or TSC2 gene is defective, cell growth is not adequately supressed and tuberous sclerosis complex results. Hamartin, tuberin, and mTOR are expressed in many different organs throughout the body, which explains why so many organs can be affected by TSC.  However, researchers are still working diligently to figure out why TSC is manifested so differently between different people.

Are the Tumors Cancerous?


What Is the Normal Life Expectancy of an Individual with TSC?


Since There Is No Cure, What Can Be Done?




Diagnostic Criteria and Survelliance Recommendations

Diagnostic Criteria




4. Shagreen patch 4. Retinal achromatic patch
5. Multiple retinal hamartomas 5. Multiple renal cysts
7. Subependymal giant cell astrocytoma 7. Sclerotic bone lesions
8. Subependymal nodule (>2)
9. Cardiac rhabdomyoma
10. Lymphangioleiomyomatosis (LAM)**
11. Angiomyolipomas (>2)**
Definite TSC: Two major features or one major feature with 2 minor features. Possible TSC: Either one major feature or > 2 minor features. **A combination of the two major clinical features LAM and angiomyolipomas without other features does not meet criteria for a Definite Diagnosis.

Surveillance Recommendations in TSC

At the time of diagnosis, many medical tests are performed. Individuals and parents should also be aware of routine testing that needs to be performed.  The following tables show suggested surveillance screening for TSC:



Brain MRI with and without gadolinium Yes Every 1-3 years up to age 25; periodically as adults if SEGAs present in childhood
Electroencephalogram (EEG) Yes; if abnormal, follow-up with 24-hour video EEG Routine EEG determined by clinical need; video EEG when seizure occurrence is unclear or when unexplained behavioral or neurological changes occur
TAND checklist Yes At least annually at each clinical visit
Comprehensive evaluation for TAND If warranted by TAND checklist analysis At key development time points (years):   0-3, 3-6, 6-9, 12-16, 28-35, and as needed thereafter
Counsel parents of infants Educate parents to recognize infantile spasms* Not applicable


Complete eye exam with dilated fundoscopy Yes Annually if lesions or symptoms identified at baseline
Detailed skin exam Yes Annually
Detailed dental exam Yes Every 6 months
Panoramic radiographs of teeth If age 7 or older At age 7 if not done previously


Fetal echocardiography only if rhabdomyomas identified by prenatal ultrasound Not applicable
Echocardiogram Yes in children, especially if younger than 3 years Every 1-3 years if rhabdomyoma present in asymptomatic children; more frequently in symptomatic individuals
Electrocardiogram (ECG/EKG) Yes Every 3-5 years; more frequently if symptomatic


Blood pressure Yes Annually
Abdominal MRI Yes Every 1-3 years
Glomerular filtration rate (GFR) test Yes Annually


Clinical screening for LAM symptoms** Yes At each clinic visit
Pulmonary function test and 6-minute walk test In all females age 18 or older; in adult males only if symptomatic Annually if lung cysts detected by high resolution computed tomography (HCRT)
High resolution computed tomography (HCRT) of chest Yes Every 2-3 years if lung cysts detected on HRCT; otherwise every 5-10 years
Counsel on risks of smoking and estrogen use In adolescent and adult females At each clinic visit for individuals at risk of LAM


Genetics consultation Obtain 3-generation family history Offer genetic testing  of TSC1/2 and counseling if not done previously in individuals of reproductive age
*Treat infantile spasms with vigabatrin as first-line therapy.  Adrenocorticotropic hormone (ACTH) can be used as a second-line therapy if vigabatrin treatment is unsuccessful.
**Evaluate for LAM when symptoms such as unexplained chronic cough, chest pain, or breathing difficulties are present including exertional dyspnea and shortness of breath.